Pathology Outlines
Right Atrial Myxoma
Images and discussion contributed by: Pallavi Khattar, M.D. (New York Medical College at Westchester Medical Center), Puneet Bedi, M.D. (Brookdale University Hospital and Medical Center, New York) and John T Fallon, MD, PhD (New York Medical College at Westchester Medical Center)
Clinical history:
A 75 year old woman with edema on bilateral extremities and weight gain. CT scan chest revealed cardiomegaly and a mass in the right atrium.
Gross description:
Gross examination showed a large pedunculated soft gelatinous red-brown mass measuring 5.3 x 4.5 x 2.2 cm, weighing 45.4 g. Cut sections showed variegated appearance with tan-pink, red-brown to yellowish-white cut surface, with white mucoid areas of degeneration and hemorrhage.
Discussion:
Cardiac myxomas are the most common primary tumor of heart (~40-50%, Interact Cardiovasc Thorac Surg 2007;6:636). Approximately 90% are solitary and pedunculated. Most cardiac myxomas originate in the left atrium (87.7%) and less frequently from the mitral valve (6.1%), in the right atrium (4.1%) and bilaterally in the left and right atria (2.0%, Eur J Cardiothorac Surg 2002;22:971). Diagnosis may be a challenge because of nonspecific symptoms. These tumors are known to arise from multipotent mesenchyme capable of neural and endothelial differentiation.
Grossly, the tumors are pedunculated with a short stalk; rarely sessile. The tumor has variegated appearance varying from a soft, gelatinous, papillary mass to a firm, smooth mass. Cut surface, frequently shows areas of hemorrhage and necrosis.
Microscopically, myxomas are composed of polygonal, bipolar or stellate “lepidic” cells that have round to oval nuclei with inconspicuous nucleoli, eosinophilic cytoplasm and indistinct cell borders. Tumor cells may be scattered singly, aggregate in small nests or cords, or forms rings surrounding vascular channels.
Ten percent of cardiac myxoma cases are associated with Carney complex; which is a rare autosomal dominant syndrome. Carney Complex (CNC) is characterized by pigmented lesions of skin, myxomas of the mucosa, skin and heart, and multiple endocrine tumors. The disease is caused by inactivating mutations or large deletions of the PRKAR1A gene located at 17q22-24, coding for the regulatory subunit type I alpha of protein kinase A (PKA) gene. Most recently, components of the complex have been associated with defects of other PKA subunits, such as the catalytic subunits PRKACA (adrenal hyperplasia) and PRKACB (pigmented spots, myxomas, pituitary adenomas, Eur J Endocrinol 2015;173:M85).
Most atrial myxomas are benign and can be removed by surgical resection (Interact Cardiovasc Thorac Surg 2015;21:183).
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Right Atrial Myxoma
Images and discussion contributed by: Pallavi Khattar, M.D. (New York Medical College at Westchester Medical Center), Puneet Bedi, M.D. (Brookdale University Hospital and Medical Center, New York) and John T Fallon, MD, PhD (New York Medical College at Westchester Medical Center)
Clinical history:
A 75 year old woman with edema on bilateral extremities and weight gain. CT scan chest revealed cardiomegaly and a mass in the right atrium.
Gross description:
Gross examination showed a large pedunculated soft gelatinous red-brown mass measuring 5.3 x 4.5 x 2.2 cm, weighing 45.4 g. Cut sections showed variegated appearance with tan-pink, red-brown to yellowish-white cut surface, with white mucoid areas of degeneration and hemorrhage.
Discussion:
Cardiac myxomas are the most common primary tumor of heart (~40-50%, Interact Cardiovasc Thorac Surg 2007;6:636). Approximately 90% are solitary and pedunculated. Most cardiac myxomas originate in the left atrium (87.7%) and less frequently from the mitral valve (6.1%), in the right atrium (4.1%) and bilaterally in the left and right atria (2.0%, Eur J Cardiothorac Surg 2002;22:971). Diagnosis may be a challenge because of nonspecific symptoms. These tumors are known to arise from multipotent mesenchyme capable of neural and endothelial differentiation.
Grossly, the tumors are pedunculated with a short stalk; rarely sessile. The tumor has variegated appearance varying from a soft, gelatinous, papillary mass to a firm, smooth mass. Cut surface, frequently shows areas of hemorrhage and necrosis.
Microscopically, myxomas are composed of polygonal, bipolar or stellate “lepidic” cells that have round to oval nuclei with inconspicuous nucleoli, eosinophilic cytoplasm and indistinct cell borders. Tumor cells may be scattered singly, aggregate in small nests or cords, or forms rings surrounding vascular channels.
Ten percent of cardiac myxoma cases are associated with Carney complex; which is a rare autosomal dominant syndrome. Carney Complex (CNC) is characterized by pigmented lesions of skin, myxomas of the mucosa, skin and heart, and multiple endocrine tumors. The disease is caused by inactivating mutations or large deletions of the PRKAR1A gene located at 17q22-24, coding for the regulatory subunit type I alpha of protein kinase A (PKA) gene. Most recently, components of the complex have been associated with defects of other PKA subunits, such as the catalytic subunits PRKACA (adrenal hyperplasia) and PRKACB (pigmented spots, myxomas, pituitary adenomas, Eur J Endocrinol 2015;173:M85).
Most atrial myxomas are benign and can be removed by surgical resection (Interact Cardiovasc Thorac Surg 2015;21:183).
Click here to see topic.